Stoker



July 26, 1938.

Filed sTEvENsoN STOKER March so, 193e 2 Sheets-Sheet l l a/Weya R. E. STEVENSONv STGKER v Filed Marchfso, 193s July 26, 1938.

2 Sheets-Sheet 2 6 omega n Patented July 26, 1938 UNITED STATES PATENT ortica 'I Claims.

This invention relates to the art of solid fuel stokers and has for one of its primary objects the provision of means for creating combustion of the fuel immediately around the enclosing wall of the combustion chamber rather than having the combustion occur in the central portion of that chamber with a dead area therearound as has been the usual practice in the ordinary domestic Stoker.

A further primary object of my invention is to provide a very simple and elcient distributing device whereby the fuel as well as the airforsupporting combustion is delivered in close proximity to the outer wall of the combustion chamber without the necessity of having to employ moving members immediately adjacent the combustion zone. Another primary object of the invention is to provide means for feeding the fused ashes or clinkers resulting from combustion of the fuel to a central collecting plate from which they may be removed at will or even allowed to collect without interfering with the combustion in the annular zone therearound.

A still further important object of my invention is to provide a structure which may be installed in furnaces previously built without having to build up cement llers or the like and which will be adaptable through different sizes of ller plates to the varying size of combustion chambers encountered.

These and other objects and advantages of the invention will become apparent to those versed in the art in the following description of my invention as drawn to two possible forms illustrative of the structural embodiment of the invention, as shown in the accompanying drawings, wherein Fig. 1 is a vertical sectional view through a structure embodying my invention with parts broken away;

Fig. 2, a transverse vertical section on the lin'e 2--2 in Fig. 1; v

Fig. 3, a horizontal transverse section with 'parts broken away on the line 3-3 in Fig.l 1, and

Fig. 4, a vertical section of a form of the in- Vention modified from that shown in Fig. 1. Figs. 1 and 4 are in part diagrammatic.

Like characters of reference indicate like parts throughout the several views in the drawings.

The invention may be applied to any ofthe usual and well known types of heating units, a

matically illustrated in the forms herein shown Awherein a combustion chamber I0 is shown surrounded by the usual jacket II from which hot air is taken for heating purposes. The jacket II is provided with a customary ash pit door openhot air heating unit being more or less diagram- (Cl. 11th- 45) forming a seal or closure over the top side of the air box portion I5. Above this end Il is positioned an inverted conical air chamber I8 mounted in spaced relation in and above the end I'l as indicated in Fig. 1. The air chamber I8 is interconnected with th'e air box I4 by means of suitable nipples I9'extending across the annular passageway formed between the end I1 and the air chamber I8 thereabove.-

The upper side of this chamber I8 is provided with a lid or cover 20 which is preferably mounted thereon to be revoluble in a horizontal plane about a central bolt 2| which has its lower end anchored or secured in the chamber I8. This cover 20 is spaced upwardly from the upper edge of the chamber IB by means of lugs 22 so as to provide annular slit-openings 22 between the cover and the upperend of the wall of the chamber I8.

The members so far described are mounted in rey lation to the combustion chamber I0 to have the cover plate 20 at the bottom or inthe lower portion of the chamber I0. In order to complete the enclosure of the lower end of the chamber I6 (from which the ordinary grate bars have been removed as is customary) I employ a plurality of ller plates 23 of any suitable number to extend from the top of the junctureof the end I'l with` the air box portion I5 in an outwardly Haring manner to meet and rest upon the lower end of the combustion chamber wall or ring 24, this ring being in the ordinary assembly,` that which has originally supported the removed grate bars. These filler plates 23 are made to fit together snugly about their side edges and are made in sets varying in size to meet the requirements of the varying diameters of the combustion chambers encountered. In other words, for each different size of fire pot, there is a specified set of plates 23 to ll in between the wall of that fire pot'and the pipe end I1.

In practice, fuel is fed from any suitable hopper 2l' in the usual manner by a conveyer screw 25 through the pipe I3 and thereby forced into the discharge end I1 which dares upwardly as above indicated. Continued feeding of fuel into this end causes the fuel to be forced on up over the plates 23 to assume some such upper positions as indicated by the dotted lines in Fig. 1, Air is forced under pressure from a suitable blower 26 in the usual manner through a conducting pipe 21 into the air box I4 from which it may escape through the nipples I9 into the chamber I8 and discharge therefrom through the openings 22 into the fuel therearound and below the upper level thereof. Combustion of the fuel is had as may be readily understood within this annular zone in immediate proximity to the wall of the chamber In where it is practically under the influence of the outwardly flowing air from the openings 22 which tend to create a blast directed toward the walls of the furnace.

It is to be understood that in any hot air type of furnace as herein illustrated, it is the wall of the combustion chamber which is employed to transmit heat from the burning fuel to the air between the jacket and that chamber. Therefore it is appreciated that the heating unit becomes more efllcient with the utilization of the heat of combustion to heat these outer walls directly rather than permitting the combustion to occur centrally of the chamber and at a distance removed from the outer Wall.

The air chamber I8 is securely anchored by nipples I9 so that the fuel rising therearound does not lift it out of position and the cover 20 is made to be revoluble so that it may be turned from time to time by any means such as a poker being in- Iserted in one of the-openings 22 to engage a lug I'22 and thereby free the openings of any accumulation of ash or fuel dust that may occur. At times the air pressure in the chamber I8 may not be sufcient to maintainthat opening. Such a condition would occur of course during automatic control of the air or fuel or both as is the common practice. It is to be noted that the filler plates 23 have their lower ends anchored around the annular flange of the pipe end I'I so as to prevent outward displacement as the fuel is fed up over .the plates. This mounting in the particular form herein Shown is accomplished by providing a recess within the lower end of each plate which may fit over a projection such as the head of a bolt 28 employed to interconnect the flange of the pipe end I1 with the air box portion I5, Fig. 1. In the form herein shown in Fig. 4, the air box of the form shown in Fig. l is omitted and an air conductor 29 is carried along under the fuel pipe I3' to discharge directly into the lower end f the chamber I8'. Otherwise the structure remains the same in that fuel is fed by the conveyer screw 25' into the discharging end I 'I' so that the fuel is carried directly upwardly in an outwardly aring annular passageway around the chamber I8'. The principal distinction between the form shown in Fig. 4 and that shown in Fig. 1 is in the manner of supplying the air to discharge from the chamber I8' throughthe openings 22' to support combustion adjacent vthe outer wall of the 'combustion chamber.

While I have herein shown and described my invention in the forms as now best known to me, it is obvious that structural variations may be lemployed without departing from the spirit-of the invention and I, therefore, do not desire to be limited to that precise form beyond the limitations which may be imposed by the following claims.

I claim:

f ...1. In an underi'eed stoker for supplying solid fuel annulus toward the chamber wall and a circular rotatable plate covering the center of the annulus and above and aiding in the direction of the air blast, said plate having lugs manually actuated to rotate the plate.

v2. In an underfeed Stoker, the combination of a fire box having a bottom, a fuel feeding pipe having an upwardly fiaring end directly on th.- discharge end of the pipe spaced below the bottom of the fire box, an inverted conical air distributing chamber spaced in and above the flaring end of the feed pipe, a cover plate closing the upper end of the air distributing chamber, having air outlets between it and the walls of the chamber and lugs by which it is manually rotated, means for supplying air under pressure to the chamber and a closely fitting series of plates closing the space between the flaring end of the fuel feeding pipe and the bottom of the fire box.

3. In an underfeed stoker, in combination with a fire-box provided with an external wall, a fuel feeding pipe below the fire-box extending to the space below the fire box and provided with an upwardly flaring end arranged to discharge into the fire box. an inverted conical air distributing chamber wall located in the upwardly flaring end of the fuel feeding pipe, a cover plateover the upper end of the cone having air outlets next to the Walls of the cone directed toward the wall of said fire-box, means for supplying air to the air chamber,and filler plates mounted on said flaring end portion and extending upwardly and outwardly to said wall.

4. In an underfeed stoker, in combination with a fire-box provided with an external wall, a fuel feeding pipe below the fire-box extending to the space below the fire box and provided with an`upwardly flaring end arranged to discharge into the fire box, an inverted conical air distributing chamber wall located in the upwardly flaring end of the fuel feeding pipe, a cover plate over the upper end of the cone having air outlets next to the walls of the cone directed toward the wall of said fire-box, means for supplying air to the air chamber, and filler plates mounted on said ilaring end portion and extending upwardly and outwardly to said wall, said outlets being at approximately .the same elevation as that of the upper ends of said ller plates.

5.' In an underfeedlstoker, in combination with a fire-box provided with an external wall, a fuel feeding pipe below the fire-box extending to the space below the fire box and provided with an upwardly aring end arranged to discharge into the flre box, an inverted conical air distributing chamber wall located in the upwardly flaring end of the fuel feeding pipe, a cover plate over the upper end of the cone having air outlets next to the walls of the cone directed toward the' wall of said ilre-box, means for supplying air to the air chamber, and filler plates mounted on said flaring end portion and extending upwardly and outwardly to said wall, said-filler plates being of sufficient number and size to close the space between the nre-box and the top of the flaring end of the fuel pipe.

6. In an underfeed stoker, in combination with a fire-box provided with an external wall, a fuel vfeeding pipe below the fire-box extending to the iii) ' nieuwe the fire box, an inverted conical air distributing chamber wall located in the upwardly haring end of the fuel feeding pipe, a cover plete over the upper end of the cone having air outlets next to the walls of the cone directed toward the wall of said fire-box, means for supplying air tothe air chamber, and ller plates mounted on said daring; end portion and extending upwardly and out-L wardly to said Wall, and lugs between said plate und conical chamber wall supporting the plate4 and defining said outlets below the plate.

7. In an underfeed Stoker, the combination with a furnace having an ash pit and ash pit door. und provided with a iire box having a wall, of a fuel supply pipe below the nre box extending through the, ash pit door, an air supply con-- ductor extending with the fuel pipe through said door, an upwardly flaring end connected with the discharge end of said pipe below the re box, an inverted conical air distributing chamber above said flaring end, a rotatable circular cover limitingr the air discharge from the distributing chamber, a plurality of ller plates continuing from the end of said upwardly daring end of the conductor to the wall of the hre box to deiine an annular fuel directing passageway and air conductingo 10- means interconnecting said air chamber and said air supply conductor, said chamber having air outlets at its upper end directed toward said me box well.,

ROBERT E. STEVENSON. 

